Improving Multicast Communications Over Wireless Mesh Networks

In wireless mesh networks (WMNs) the traditional approach to shortest path tree based multicasting is to cater for the needs of the poorest performingnode i.e. the maximum permitted multicast line rate is limited to the lowest line rate used by the individual Child nodes on a branch. In general, this meansfixing the line rate to its minimum value and fixing the transmit power to its maximum permitted value. This simplistic approach of applying a single multicast rate for all nodes in the multicast group results in a sub-optimal trade-off between the mean network throughput and coverage area that does not allow for high bandwidth multimedia applications to be supported. By relaxing this constraint and allowing multiple line rates to be used, the mean network throughput can be improved. This thesis presents two methods that aim to increase the mean network throughput through the use of multiple line rates by the forwarding nodes. This is achieved by identifying the Child nodes responsible for reducing the multicast group rate. The first method identifies specific locations for the placement of relay nodes which allows for higher multicast branch line rates to be used. The second method uses a power control algorithm to tune the transmit power to allow for higher multicast branch line rates. The use of power control also helps to reduce the interference caused to neighbouring nodes.Through extensive computer simulation it can be shown that these two methods can lead to a four-fold gain in the mean network throughput undertypical WMN operating conditions compared with the single line rate case

The impact of inter-vehicle communication on vehicular traffic

The work addresses communication networks established over radio equipped vehicles in our everyday road traffic, so called Vehicular Ad Hoc Networks (VANETs), and discusses their impact on two major goals, namely traffic safety and traffic efficiency. For both objectives, the thesis proposes an appropriate modeling of the essential building blocks Traffic, Communication and Application and enables impact assessment studies by means of implemented simulation tools

The impact of inter-vehicle communication on vehicular traffic

The work addresses communication networks established over radio equipped vehicles in our everyday road traffic, so called Vehicular Ad Hoc Networks (VANETs), and discusses their impact on two major goals, namely traffic safety and traffic efficiency. For both objectives, the thesis proposes an appropriate modeling of the essential building blocks Traffic, Communication and Application and enables impact assessment studies by means of implemented simulation tools

Detailed Simulation of Large-Scale Wireless Networks

In this paper, we present WiFra, a new framework for the detailed simulation of very large-scale wireless networks. WiFra is based on the parallel and distributed simulation approach and provides high scalability in terms of size of simulated networks and number of execution units running the simulation. In order to improve the performance of distributed simulation, additional techniques are proposed. Their aim is to reduce the communication overhead and to maintain a good level of load-balancing. Simulation architectures composed of low-cost Commercial-Off-The-Shelf (COTS) hardware are specifically supported by WiFra. The framework dynamically reconfigures the simulation, taking care of the performance of each part of the execution architecture and dealing with unpredictable fluctuations of the available computation power and communication load on the single execution units. A fine-grained model of the 802.11 DCF protocol has been used for the performance evaluation of the proposed framework. The results demonstrate that the distributed approach is suitable for the detailed simulation of very-large scale wireless networks

ARTIS: Advanced RTI System

ARTIS: Advanced RTI System The Advanced RTI System (ART\uccS) is a middleware for Parallel and Distributed Simulation (PADS) supporting massively populated models. The middleware provides to system modellers an easy-to-use software tool in which is possible to build simulation models that can be executed using a sequential (monolithic) or parallel/distributed approach. On top of ARTIS, the Generic Adaptive Interaction Architecture (GAIA) framework provides an environment in which the simulation entities are adaptively clustered based on their communication patterns. The aim of this mechanism is to reduce the communication overhead of the PADS and to improve the Load Balancing of the execution architecture. In practice, GAIA offers to the final user a clear and elegant paradigm for the implementation of simulation models. The software, that is free for educational and research purposes, can be downloaded from the research group website: http://pads.cs.unibo.it on the same website is possibile to find some documentation on the usage of the sofware and the FAQs. Direct links for software download: http://pads.cs.unibo.it/download/artis/ARTIS-2.0.0.tar.bz2 (GNU/Linux, 32-bit version) http://pads.cs.unibo.it/download/artis/ARTIS-2.0.0_x86-64.tar.bz2 (GNU/Linux, 64-bit version) The last version of ARTIS (version 2.0.0) integrates both the middleware, the GAIA framework, many simulation models and all the necessary scripts and tools for the evaluation of complex systems. The most part of this software is provided in both binary and source code versions. The ARTIS/GAIA software has been described/used in the following research papers (PARTIAL LIST): BOOK CHAPTERS - L. Bononi, G. D'Angelo, L. Donatiello. Parallel and Distributed Simulation of Wireless Mobile and Sensor Networks. Performance Evaluation of Parallel, Distributed and Emergent Systems. (Volume 1 in Distributed, Cluster and Grid Computing), M. Ould-Khaoua and G. Min (Editors). Ed. Nova Science. 2007. ISBN: 1-59454-817-X. INTERNATIONAL JOURNALS - G. D'Angelo, M. Bracuto. Distributed Simulation of Large-Scale and Detailed Models. International Journal of Simulation and Process Modelling 2009 - Vol. 5, No.2 pp. 120 - 131. Inderscience Publishers. ISSN (Online): 1740-2131 - ISSN (Print): 1740-2123. - L. Bononi, M. Di Felice, G. D'Angelo, M. Bracuto, L. Donatiello. MoVES: A framework for parallel and distributed simulation of wireless vehicular ad hoc networks. Elsevier's Computer Networks (ComNet) Journal. Volume 52, Issue 1, 2008, pp. 155-179. ISSN: 1389-1286 CONFERENCES AND WORKSHOPS - G. D'Angelo, S. Ferretti. Simulation of Scale-Free Networks. 2nd ACM/ICST International Conference on Simulation Tools and Techniques (SIMUTools 2009). ISBN: 978-963-9799-45-5 - G. D'Angelo, G. Rossi. Parallel and Distributed Simulation of Coalition Structure Generation in Cooperative Multi-agent Systems. 22th ACM/IEEE/SCS Workshop on Principles of Advanced and Distributed Simulation (PADS'08). ISBN 978-0-7695-3159-5 - M. Bracuto, G. D'Angelo. Detailed Simulation of Large-Scale Wireless Networks. 11-th ACM/IEEE International Symposium on Distributed Simulation and Real Time Applications (DS-RT 2007). ISBN 0-7695-3011-7 NOTE: the complete list of publications based on the ARTIS/GAIA middleware can be found in the attached file